Former police detective Carl Casilli has been sentenced to nine months' jail.

ABC News

A former Perth police detective has been jailed for unlawfully passing information to a lawyer he was having an affair with.

Carl Casilli was a detective sergeant in the central metropolitan district between 2008 and 2013 when he accessed information on the police database and gave it to his lover, who was a lawyer.

He also admitted giving her a copy of a video interview with a murder suspect, and providing her with information about phones that were tapped.

Casilli was one of the detectives who worked on the 2007 murder of Corryn Rayney, the wife of a high-profile department of prosecutions lawyer who was accused of her murder, but the offences are not related to that case.

Mr Rayney was cleared of all charges relating to the death of his wife, whose murder remains unsolved.

Casilli's lawyer Nick Lemmon rejected that assertion, maintaining much of the information his client accessed would have been made available to the lawyer anyway, because it was about people she was representing.

He argued Casilli provided the lawyer with the video recording of an interview because he was interested in getting her views on his interviewing technique.

Casilli was facing 17 charges.

A Perth magistrate today sentenced Casilli to a total of nine months' jail and fined him $2,000.